Slashdot videos: Now with more Slashdot!

View

Discuss

Share

We've improved Slashdot's video section; now you can view our video interviews, product close-ups and site visits with all the usual Slashdot options to comment, share, etc. No more walled garden! It's a work in progress -- we hope you'll check it out (Learn more about the recent updates).

f00Dave writes "Researchers have discovered "a new physical phenomenon, electrostatic rotation, that, in the absence of friction, leads to spin". I'm a bit skeptical about the implied relationship between physical "spin" (as in rotation) and quantum "spin", however. Still, this is the sort of scientific advance that renews my faith in the system. Go nerds! =]"

After you tape the toast to the cat, you have to seal it in a blackbox, flip the box over, the cat will be suspended by the conflicted laws of phsics. unfortunetly you cannot observe it, as soon as you open the box, the cat will have eaten the toast. an interesting note, while the cat is in the box, and unobserved, he knows the correct keys to all possible encryptions. Dont tell the humane society OK...

I.e., it does not answer the question. In fact, thearticle directly linked contained nothing which would allowyou to rigorously infer whether the effect observed wasa newly observed consequence of the laws of Gauss and Faraday,or something contradictory to the implications of QED asit is currently formulated.

You can not determine from the article under what circumstancesthe angular accelleration occurs. You can not determine whetherit is linear, logarithmic, exponential, hyperbolic, or parabolic.You cann

Yeah, we all raced to get that one in. Bastard. My only is to provide the entire scene:

That night, in bed...

Marge: I'm worried about the kids, Homey. Lisa's becoming very obsessive. This morning I caught her trying to dissect her own raincoat.Homer: [scoffs] I know. And this perpetual motion machine she made today is a joke! It just keeps going faster and faster.Marge: And Bart isn't doing very well either. He needs boundaries and structure. There's something about flying a kite at night that's so

Oh my God... I had the same idea! Did yours come to you in a dream of a burning president? Though I don't think I've put the parts together right. All I keep getting is a cool new alternative to the telephone. I can't wait to take out a patent before Jeff Bozo at Amazon.com beats me to it!

Unlimited spin would be nice for turntables and whatnot (imagine the mew re-mixes at ungodly RPMs) but seriously what would this be used for? I don't know much about physics, so could someone please elucidate the commercial value of this discovery?

Maybe that's the cool thing about scientific curiosity - the things you discover don't have to have commercial value in order to be discovered.

Consider this: when it was determined that a current flowing in a wire produces a magnetic field, or when Faraday discovered that moving a magnet near a wire or coil of wire can produce a voltage, I'm sure a lot of people said, "but seriously, what would this be used for?" And they probably said the same thing about countless other things that were discovered in situations where the effect was so small that they had no apparent use.

Of course now we look back and say, "what a dumb question! How could they now know these things could be useful?" And maybe 200 years from now somebody will look at this archived announcement on Slashdot and say the same.

Then again, maybe this will turn out to be a misinterpretation of the experimental observation. Time will tell...

William Gladstone, the Chancellor of the Exchequer, was invited to witness a demonstration of Faraday's electrical equipment. Gladstone asked, "This is quite interesting, Faraday, but of what practical worth is it?" Faraday replied, "One day, sir, you may tax it."

Nanotech basically. They have basically discovered a way to use a distribution of electric charges on a configuration of three sphere to start one of the spheres rotating. This is different from current electric motors; they use magnetic fields to start things rotating. This kind of engine would use a lot less current to generate motion than conventional electromagnetic motors. This would be good for building little machines; it's really hard to make electromagnets at the subatomic scale, but metallic s

That remember me when Becquerel discovered that uranium salts caused images on photographic plates. Surely he or most of the people of this time didn't think that it could give us, well, all that is related, from atomic bombs and clocks to new energy sources, a lot of advances in medicine, a big leap in the understanding of the universe, and more.

Atomic clocks did not result from the discovery of uranium's radioactivity. In fact, they don't involve radioactivity at all. Here's a link [navy.mil] that explains how they work. They are called 'atomic' because they rely on electronic transitions in isolated atoms

I'm a bit skeptical about the implied relationship between physical "spin" (as in rotation) and quantum "spin", however. Still, this is the sort of scientific advance that renews my faith in the system.

What system are we talking about? Why does faith need to be renewed in it? What, have you lost faith in physics because it doesn't discover new laws every day?

Even so, one needs to keep perspective. At risk of sounding religous: if that sort of thing makes one "lose one's faith" in "the system", then that faith can't have been very strong to begin with. Meaning, if you really understand the scientific method, then you'd realise that over time it WILL expose the fakes, and we can actually be quite relaxed and confident about that. The system itself is sound: the only thing we should worry about is society giving up this system in favour of another. To quote Carl Sagan: "At the heart of science is an essential balance between two seemingly contradictory attitudes--an openness to new ideas, no matter how bizarre or counterintuitive, and the most ruthlessly skeptical scrutiny of all ideas, old and new. This is how deep truths are winnowed from deep nonsense."... "At the same time, science requires the most vigorous and uncompromising skepticism, because the vast majority of ideas are simply wrong, and the only way to winnow the wheat from the chaff is by critical experiment and analysis.".

This essay by Jearl Walker [haxial.com] is an interesting and insightful read that relates this notion of "faith" in physics (read right up to the end).

Consider the pace of development of technology versus that of science. Through the course of human history, (major) scientific discoveries are indeed rare, but occur at reasonably regular intervals. We've been quite overdue for a non-technological discovery for quite a while, now. Also, I had *no* idea this story would be accepted for anything but science.slashdot.org (if at all), so didn't spend time 'dumbing down' my presentation. Oops.;-)

The article DOES seem to imply the quantum spin is similar to the physical. It was also light on the tehnical description of the phenomenon.

I suspect this is one of the regular release articles, just like nVidia being forced to put out new versions of cards every 6 months no matter what the developments. To keep funds secured, scientists have to do these things, on regular intervals produce press reports about things they SUSPECT might be revolutionary, followed by possible applications in medical, milit

Linkage by juxtaposition is a common logical fallacy, prevalent in the media, unfortunately. A desensitization to which was why I added that remark: it was not indended for the careful reader, but for the "average/. reader who has an interest in science". Yeah, that's an odd market, I'm sure. =)

It sounds like they're saying the angular velocity will increase if the rotation is frictionless. Why won't this phenomenon cancel out at equilibrium amount of friction and keep the object spinning at constant angular momentum forever? I should also accelerate an object with a small amount of friction but at a slower rate than a frictionless object.

In any case, we're talking about building a perpetual motion machine here and throwing the first law of thermodymics out the window. This makes the cold fusion claims sound pretty tame. At least they said where they were getting their energy, here it seems to come from nowhere.

It sounds like they're saying the angular velocity will increase if the rotation is frictionless.

Yup, thats what they said.

Why won't this phenomenon cancel out at equilibrium amount of friction and keep the object spinning at constant angular momentum forever?

They didn't say it wouldn't. Presumably that is what would happen.

I[t] should also accelerate an object with a small amount of friction but at a slower rate than a frictionless object.

Yup. In their experiment the wire supporting the sphere was applying a counter-torque, it was just small enough that the new force was able to overcome it. By calculating the amount of torque generated by the wire after the number of revolutions made by the ball, they would have the static force generated.

In any case, we're talking about building a perpetual motion machine here and throwing the first law of thermodymics out the window.

Not likely. The kenetic energy of the rotation is probably balanced by a reduction in the net charge on the object. What they've got is basicly a really, really weak electric motor. A charged object in free fall would probably increase its angular momentum until it didn't have any charge left (then gravitational effects would probably eventually bleed all that energy back off again).

What I wonder is if its reversable, so rotation can be converted into a charge on the object.

Nowhere do i see the words, "in a vacuum." So that leaves, 'without friction' as an useless phrase? or maybe this is a standard term that i'm missing? Me, i'd assume that spinning in air causes friction (not to mention dizziness.)

Now if they want to measure political spin, we have to wait to see what research grants they apply for next...(sorry, couldn't help it.) Seriously- how do they do this without friction?

I see hidden importance in the exact placement of the spheres, the angles and distances at which they are separated, which are not explained in the article. What I see happening is the spheres being positioned in such a way that the Coulomb forces act primarily (entirely?) in a tangential fasion on the two free-floating spheres, resulting in net rotation instead of net axial displacement. Could be merely a trigonometric stunt rather than new electrostatic observations.

"Faith is belief in something which you know to be false -- Arthur Clarke." More proof that AC is going loopy.

If a boy comes up to you and says "I have a red ball in my room" and you believe him, you have faith that he told yo the truth. But at know time do you know what he says is true. Even if you went to his room and didn't find the ball, doesn't mean it wasn't there when he told you.

The article shows much more clearly than the pop news release that the rotation has nothing to do with quantum spin, and is entirely a classical electrostatic phenomenon. I will try to translate the article briefly:

Essentially, when you apply a charge to the first of the three metal spheres, the charges all repel each other and go to the outside of the first sphere. This exerts a repulsive force against the like charges on the other two spheres, causing an imbalance as more charges are pushed to the far side of the spheres (from the first one) than are on the close side of the spheres. Then, because the second and third spheres have an imbalanced charge distribution, they also exert forces on each other which further displace the charges.

The displaced charges result in a potential which isn't perfectly balanced like two spheres would be, and the resulting calculation shows an interaction proportional to 1/(r^6), where r is the separation distance, which yields a rotation.

That seems to make more sense... sounds like these boys have found a new way to make a (potentially) really small motor using scientific laws that are about 200 years old. Kudos to them, and great engineering work!

1. they apply a current through a metal ball. Which induces a magnetic field.

2. They place a second metal ball near the first ball. The proximity to the first magnetic field in the second ball induces a electric potential in the second ball.

3. The third ball may be electrically connected to the suspension wires of either or both balls 1 and 2. Hence, it induces a magnetic field of it's own. The relationship between the magnetic fields in th

I do have one initial concern, and that's the temporal juxtaposition of this announcement with April 1. Is three days of separation sufficient to assure that we're not seeing some kind of delayed effect here?

I didn't notice the date when I first read it. And I scanned for one, too. My bad.

Yet it occurs to me that there is a possibility that this was submitted to UCR News on Apr 1 as a joke that whooshed right over the editors' heads... and the Apr 2 date is normal artifact of processing.

I'm sure that either way, there will soon be further stories about this.

From my understanding of the article they applied an electrical potential to the sphere but no real current. They were studying static electricity. Although some energy is put into the sphere when it is charged, no energy is moved to the sphere after it is charged. If the sphere continues to rotate after it is fully charged some other source of energy (or experimental error) would be necessary to explain the results.

What is unique about this experiment is that a magnetic field is generated by a current but

More seriously though: both the articles in Applied Physics Letters and in Europhysics letters are followed by errata (see publication list [ucr.edu]. So they were at least partially wrong which is not a good start for dethroning a century-old theory.

So, they created an iron sphere with a magnetic field, and it started to spin, ever so slightly. Don't you think that this field could just have been moving through some other magnetic field, and this caused the spin?

The article is very confusing, and makes several leaps that even the researchers don't promulgate.

Basically, what seems to be going on here is that one charges up metal spheres to see how they interact. This is a way of testing EM theory. Now, as is commonly known, charging a metal sphere will eventually have the charge distributed uniformly on the surface, and eventually static. However, it takes a non-zero amount of time to reach t

actually, even with uniform distributed charge after charging complete, an asymmetric suspended object (like REAL WORLD BALL BEARINGS) will twist when an electrostatic field is applied until torques and forces are balanced. What a load of crap the linked article is

1. The time taken to charge up the spheres is nearly instantaneous; it only depends on the capacitance of the system, which in this case is undoubtably small. Also, in the article they state that they wait dozens of hours for the system to equilibriate before making measurements.

2. The charge is *not* uniformly induced on the two spheres not hooked up to the voltage source, which is exactly why they rotate. The *voltage* on the surface of each of the spheres is uniform (because other

The Applied Physics Letters paper is just two pages long. There is no new physics here. Here's the skinny.

Sphere A is charged up; the two others, B and C, are at different distances from A. Each sphere is polarized in a non-uniform way (because each sphere has two hemispheres, one closer to the charged sphere and the other farther... just as tides form on Earth due to the moon).

The potential at the surfaces of B and C might be uniform but the charge distributions are not: they are dipole. Due to this dipole interaction (the more negativey charge hemisphere of one sphere wants to be closer to the more positively charged surface of the other sphere), Spheres B and C then tourqe to a different angle and will either a) stay there in the presence of some friction or b) oscillate back and forth in the absence of friction. Of course, there is always some element of friction due to the air and wire, but one can compensate by also oscillating the potential of A to make positive feedback, I imagine.

The press release was, in this physics grad student's opinion, horrible. Implications that this research has some impact on our understanding of electrostatics or (gasp) quantum mechanics is irresponsible. It's a cute trick, though, and I'll bet it will find applications in mico-,nano-tech and perhaps other research areas (e.g. experiments requiring precision angular measurements [washington.edu]).

This phenomenon was purely predictable from Coulomb's law and Gauss's laws of electrostatic attraction/repulsion. Many of you should have learned about these in freshman physics. The spheres were arranged in an assymetric pattern, so rotation isn't breaking any kind of symmetry. If you arranged their spherical balls in a mirror image pattern, the rotation will reverse. The authors aren't trying to say they measured some kind of new mystical force that hasn't already been understood for 100's of years but simply that there could be an engineering application that no one had thought of before.

I'm inclined to agree with the original poster's comment that this has nothing to do with quantum mechanical spin.

Continued rotation against resistance from a static charge seems strange to me.

I wonder if they've adequately controlled against the phenomenon of "electric wind"?

They're "holding the potential constant" on the central sphere, despite any leakage from irregularities in its surface. The two uncharged spheres nearby should create a stronger field in their direction. Corona discharges toward the space between the spheres could result in a net outward motion of air there, and inward motion of air between the outer and central spheres. Friction of this air against the outer spehres would provide a rotational force, in opposite directions on the two spheres, with no net force on the central sphere.

This is funny- yesterday I was picking up a print out here in the Physics Department, and I happened to notice a stray copy of this article lying next to the printer. It is a super easy read for anyone versed in physics up to the intro-graduate level, and took up just 1 or 2 pages. The beautiful thing about this experiment is that it SCALES- in other words it works for very very small things (think nanomotors) and larger things (macroscopic systems, like the actual experimental setup). Just a beautiful p

Rotating the sphere (from rest) requires energy. Therefore, the DC voltage applied must require some current - where is it going? and what magnetic field does it produce? and how do all these fields interact? If not you could cover the spheres with insulation to maintain their charge, put them on really good bearings, and have a perpetual motion machine. At the bottom of the story is a big plug for this cool university. I suspect they're just trying to get more $tudents using neato-sounding, but bogus scien

If the spin were being shown to be a result of quantum spin. (We haven't been shown that quantum "spin" is not the mechanism by which this occurs, either.) If it were then it would imply that all these funky "Free energy" systems would actually be possible. Unfortunately, since they are putting energy into the system, it is interesting and will (I am sure) lead to advances in our understanding of the universe, but doesn't say any such thing. And here I was hoping to run my car on free energy:(

There's a good reason why the quantum spin was named spin in the first place: A charged particle with spin exhibits a magnetic moment, and so does a rotating charged sphere. However, electron spin is quantized differently from rotation, so we know it's not really rotation.